It runs under DOSBOX, this is the real deal - you can even compile and debug your games, although there is *NO* persistent saving so don't go too
crazy with it (since once you close the browser, any progress you've made is lost)

It also runs somewhat slower than the modern builds, which is to be expected since it is running a full DOS emulator.

Also nice to compare to the recent builds to see how it should act, and how it now does.